AbstractIntroduction: Integrity of the great saphenous vein (GSV) endothelium is the most important key element for long-term patency rate of grafts in coronary artery bypass graft (CABG). Storage solutions play an important role in maintaining viability of vein endothelium. Diminished nitric oxide (NO) because of endothelial dysfunction may facilitate vascular inflammation and formation of atherosclerotic plaque. Aim: So, we decided to find a reasonable alternative preservative solution instead of heparinized blood (HB) by measuring NO concentration with Griess assay. Material and Method: SVG samples were obtained from 54 patients undergoing elective CABG. 3 mm rings were stored in solutions: heparinized blood (HB), Krebs (K), Krebs + Propranolol (K+P) 6.66 g/l, Krebs + Adrenaline (K+A) 200 µl/l, and Krebs + Verapamil (K+V) 200 µl/l for 30, 45, 60 and 90 min. Nitrite concentration was measured by Griess assay at 540 nm. H&E staining was performed for histologic test. Statistical analysis was performed using SPSS (V16). Results were expressed as (Means ± SE) followed by One-Way ANOVA for finding best preservative solution. Repeated measurement test was used to investigate best time. In all analysis, (PHB=K=K+A=K+P). Also, our investigations showed that NO concentration in (K+V) has the highest rate in time 90 min (10.07±0.56, p=0.002). More than 50 percent of endothelial cells stay normal in (K+V) compare with other solutions. Conclusion: It seems that (K+V) is the best solution for the maintenance of normal physiology of SVGs endothelial cells. The most appropriate SVGs endothelial function is within 90 minutes after harvesting.